Process for the gasification of a liquid carbonaceous fuel



Jan. 1, 1957 R. WESSOLEK PROCESS FOR THE GASIFICATION OF A uqvw CARBONACEOUS FUEL Filed Jan. 21, 1955 PROCESS FOR THE GASIFICATION OF A LIQUID CARBONACEOUS FUEL Rudolf Wessolek, Gelseukirchen, Germany, assignor, by

mesne assignments, to Koppers Company, Inc., Pittsburgh, Pa., a corporation of Delaware Application January 21, 1953, Serial No. 332,383 Claims. c1. 4s--2'1s The present invention relates in general to a process for the production of valuable gases containing carbon monoxide and hydrogen, which are suitable in particular for the synthesis of hydrocarbons, and to an apparatus for carrying out this process. In particular the invention relates to the production of such gases by the gasification of liquid fuels in suspension with oxygen.

Liquid fuels in the sense of the invention are hydrocarbon oils, tars of the most widely different kind and origin, distillation residues from mineral oil distillation and from the synthesis of hydrocarbon oils, as well as fuels which are solid at normal temperatures but which upon heating become liquid, such as, for example, asphalt or even solid paraflins or the like.

The term oxygen used hereinafter is to be understood as including both pure oxygen as well as air of increased oxygen content.

The gasification of liquid fuels with the employment of oxygen in order to produce for example water gas is well known in itself. A known process consists in injecting the liquid fuel together with oxygen into a reaction chamber maintained at elevated temperature. The oxygen then reacts with the fuel in an exothermic re action, forming mainly carbon monoxide and hydrogen. With this process the mixture of the liquid fuel and oxygen takes place before the entry into the reaction chamber or at the moment of entry into the reaction chamber.

It has already been proposed to inject a liquid fuel,

if required, together with a finely divided solid fuel, into a reaction chamber at high temperature, and to direct, from a direction displaced through 180, a stream of oxygen against the stream of liquid and solid fuel, whereby at the moment and in the region of the mingling of the two streams a gasification of the fuel takes place.

These processes have not however led to the desired result. The disadvantage of the first named process consists in that a mixture of oxygen and liquid fuel already existing in the delivery pipes to the injection nozzles has an extraordinarily great tendency to ignite there, on account of the heat radiation from the hot reaction chamber, so that the exothermic reaction between fuel and oxygen proceeds in the pipes. Theoretically there exists the possibility of more or less substantially suppressing the straying of the exothermic reaction into the pipes by considerably increasing the speeds of flow within the pipes. This last feature is however, attended with the new disadvantage that the mixture of fuel and oxygen then flows into the reaction chamber with too great a speed and then too long reaction paths are required in order to permit the complete reaction of the fuel.

The second named known process has the disadvantage that a sufiiciently homogeneous suspension of the liquid fuel in oxygen cannot be achieved, so that the gasification of the fuel does not take place with the desired efliciency.

The invention proceeds upon the basis of carrying out the gasification of liquid fuels so that on the one hand striking back of the exothermic reaction into the nited States Patent supply pipes for the liquid fuel is obviated and on the other hand, a sufiiciently homogeneous mixture of fuel and oxygen is produced, which can be converted with the optimum degree of gasification into the desired gases.

The invention consists essentially in that the liquid fuel is introduced into the reaction chamber separately from the oxygen in the form of a layer of small thickness (liquid film) and that simultaneously there is directed against both surfaces of this liquid film a stream of oxygen of such thickness and at such an angle, in front of but spaced from the injection nozzle, that a homogeneous mixture of finely divided liquid droplets and oxygen is formed, which readily reacts with an exothermic reaction.

The liquid film which forms upon leaving the injection nozzles is broken up in a very short time by the stream of oxygen meeting it at both sides, whilst on account of the whirling effect resulting from the two streams of oxygen encountering each other a highly homogeneous suspension of the liquid fuel in the oxygen is formed, and this immediately ignites and forms the desired gases, on account of the heat radiation from the hot reaction walls.

The thickness of the liquid film depends on the fuel to be gasified. It can be taken as a rule that the liquid film must be the thinner the less reactive is the liquid fuel to be gasified. It has been shown that a liquid film with a layer thickness of 1 mm. and preferably 0.5 mm. is sutficiently thin to be broken up in the shortest possible time by the two streams of oxygen and to be con verted into an homogeneous suspension with the oxygen.

Tests have shown that the breaking up of the liquid film is particularly effective if the streams of oxygen are directed against the liquid film in such a way that their point of intersection lies substantially within the film.

The fact that in accordance with the invention the point of intersection between the streams of oxygen and the liquid film lies at a certain distance from the outlet opening of the nozzles, ensures that the exothermic reaction only continues in the direction of movement of the liquid film but not in a direction towards the outlet openings.

A preferred embodiment of the process according to the invention consists in injecting the liquid film in the form of a substantially closed cylinder surface into the reaction chamber and allowing the stream of oxygen to impinge on the inner and outer surface of this cylinder.

According to a further characteristic of the invention steam is injected into the space between the zone of the exothermic reaction and the hot reaction chamber walls. The purpose of this steam is firstly to protect the reaction chamber walls from a too strong irradiation by the heat developing in the exothermic zone and on the other hand to complete, by the reaction with the hot steam, the gasification of non-reacted fuel.

The liquid fuel as Well as the oxygen are preferably introduced in a preheated condition into the reaction chamber. Preheating of the fuel to about has been shown to be particularly favourable for the formation of a liquid film with the desired layer thickness.

in order to facilitate the formation of a liquid film in the form of a substantially closed cylinder surface the annular nozzle provided for the introduction of the liquid fuel is arranged so that the fuel is divided into a series of separate jets in such a way that the jets after leaving the nozzle carry out a helical movement on a cylinder surface.

In the drawing there is illustrated a part of an apparatus for carrying out the process according to the invention, in which The figure is a vertical longitudinal section through the apparatus for injecting the reaction media into the reaction chamber.

The reaction chamber of which only the injection side s illustrated in the figure, consists of refractory maerial 1 and has at its end an injection head 2. This injection head consists primarily of a central annular nozzle 3 from which the liquid film delivered at 4 enters the reaction chamber in the form of a thin-walled cylindrical surface. The free cross section of the opening of this annular inlet nozzle which has practically the form of a narrow slit is subdivided by inserts which are so arranged that the liquid fuel is divided up into separate jets flowing between the inserts and each of which carries out a helical movement on the cylinder surface. The helical movement of the individual fuel jets has the effect that the fuel after issuing from the annular slit is not distributed immediately in all directions but retains substantially the shape of a cylinder advancing generally in the main axis of the gasification chamber.

Arranged concentrically to the annular nozzle for the liquid fuel there are two similar annular nozzles 6 and 7 for the introduction of the oxygen. The supply of the oxygen to these two nozzles is effected at S for the nozzle 6 and at 9 for the nozzle 7. The directions of discharge of the oxygen nozzles do not lie as with the fuel nozzle parallel to the main axis of the reaction chamber but lie at a certain angle to this axis. in the present case the directions of the oxygen jets issuing from the nozzles 6 and 7 are so selected that the two jets intersect substantially at the cylinder surface. Through the kinetic energy of the oxygen jets which are injected under a certain pressure, the liquid film is broken up into very fine droplets which form with the oxygen an homogcneous suspension which after its ignition by means of heat radiation from the reaction chamber walls is immediately converted into a gas mixture consisting substantially of carbon monoxide and hydrogen.

The interval between the point of intersection of t e oxygen with the fuel and the outlet opening for the fuel likewise depends inter alia on the reactivity of the fuel. The more reactive the fuel is the further will the point of intersection be removed from the fuel jet. It has been shown that a spacing of the point of intersection of not less than 3 mm. is sufficient in order effectively to suppress striking back of the exothermic reaction into the fuel pipe.

At a greater inteival from the fuel and oxygen jets there is finally provided a similarly concentric annular nozzle It) through which the steam can be injected at a certain angle into the reaction chamber. The delivery of the steam takes place at 11.

In order to protect the whole burner head, which is preferably made completely of metal, from an undesirable heating by radiation from the reaction chamber, a circulatory water cooling is provided. The cooling water supplied at 12 and taken away at 13 and which preferably has a temperature of about l20 to 150 serves for cooling the part of the asification head lying remote from the central axis of the gasification head. The cooling water supplied at 14 and taken away at 15 serves for cooling the outer oxygen nozzles and the cooling water supplied at 16 and taken away at 17 for cooling the inner oxygen nozzle. The fuel nozzle itself is not directly cooled.

As explained above the gasification head according to the invention is made completely of metal and preferably of stainless steel. The intensive cooling between the three above described circulations of cooling medium ensures that even the surfaces of the gasification head directed towards the reaction chamber do not attain an undesirably high temperature. The supply pipes for the reaction media to the reaction chamber consist essentially of the intermediate spaces between pipes arranged concentrically one within another, their spacing from each other being maintained by distance pieces 17 whilst the distance pieces are provided in such numbers that on the one hand they effect the accurate centering of the interengaged pipes and on the other hand do not substantially limit the free cross section for the streams of the reaction media.

With the above described arrangement a liquid fuel of the bunker-C-oil type was gasified with 92% oxygen. The fuel as well as the oxygen was preheated to a temperature of 150. The temperature of the injected steam amounted to about With a degree of carbon gasification of above 88% there was given a useful gas which consisted of 52.6% of carbon monoxide and 42.5% of hydrogen. The carbon dioxide fraction in the useful gas amounted to only 3.7%.

I claim:

1. A process for the gasification of a liquid carbonaceous fuel which comprises injecting an annular stream of said fuel into a gasification chamber maintained at at least the ignition temperature of said fuel, injecting concurrently with and surrounding said annular stream of fuel and directed thereat an annular stream of a freeoxygen-containing gas and injecting concurrently within said annular stream of fuel and directed thereat an an nular stream of a free oxygen-containing gas, said free oxygen-containing gas being supplied in amounts insufiicient to react completely with said fuel thereby subjecting part of said fuel to combustion and gasifying sub stantially the balance of the unreacted fuel.

2. The process of claim 1 in which the fuel is preheated to about C.

3. The process of claim 1 in which the free-oxygencontaining gas is selected from the group consisting of oxygen and oxygen-enriched air.

4. The process of claim 3 in which the free-oxygencontaining gas is oxygen.

5. The process of claim 3 in which the free-oxygencontaining gas is oxygen-enriched air.

6. The process of claim 1 in which the unreacted fuel is contacted with an endothermic gasifying agent.

7. The process of claim 6 in which the endothermic gasifying agent is steam.

8. A process for the gasification of a liquid carbonaceous fuel which comprises injecting an annular stream of said fuel into a gasification chamber to follow a helical path thereinto, said chamber being maintained at at least the ignition temperature of said fuel, injecting concurrently with and surrounding said annular stream of fuel and directed thereat an annular stream of a free oxygencontaining gas and injecting concurrently within said annular stream of fuel and directed there-at an annular stream of a free oxygen-containing gas, said free oxygencontaining gas being supplied in amounts insufficient to react completely with said fuel, thereby subjecting part of said fuel to combustion and gasifying substantially the balance of the unreacted fuel.

9. A process for the gasification of a carbonaceous fuel which is liquid at a temperature of about 150 C., which comprises injecting said fuel in the liquid state as an annular stream into a gasification chamber maintained at at least the ignition temperature of said fuel, injecting concurrently with and surrounding said annular stream of fuel and directed thereat an annular stream of a free oxygen-containing gas and injecting concurrently within said annular stream of fuel and directed thereat an annular stream of a free oxygen-containing gas, said free oxygen-containing gas being supplied in amounts insufiicient to react completely with said fuel, thereby subjecting part of said fuel to combustion and gasifying substantially the balance of the unrcacted fuel.

10. The process of claim 9 in which the combustion products and the ungasified fuel are contacted with steam.

References Cited in the file of this patent UNITED STATES PATENTS 903,735 Lee Nov. 10, 1908 (Other references on following page) 5 UNITED STATES PATENTS 2,129,269 Speer Mar. 15, 1910 2,578,422 Schneider July 25, 1916 2,595,759 Chilowsky July 17, 1934 2,670,280 Chilowsky Aug. 13, 1935 5 2,702,743 McCallum Mar. 2, 1937 6 Furlong Sept. 6, 1938 Guillot Dec. 11, 1951 Buckland at 2.1. May 6, 1952 Totzek Feb. 23, 1954 Totzek Feb. 22, 1955 

1. A PROCESS FOR THE GASIFICATION OF A LIQUID CARBONACEOUS FUEL WHICH COMPRISES INJECTING AN ANNULAR STREAM OF SAID FUEL INTO A GASIFICATION CHAMBER MAINTAINED AT AT LEAST THE IGNITION TEMPERATURE OF SAID FUEL, INJECTING CONCURRENTLY WITH AND SURROUNDING SAID ANNULAR STREAM OF FUEL AND DIRECTED THEREAT AN ANNULAR STREAM OF A FREEOXYGEN-CONTAINING GAS AND INJECTING CONCURRENTLY WITHIN SAID ANNULAR STREAM OF FUEL AND DIRECTED THEREAT AN ANNULAR STREAM OF A FREE OXYGEN-CONTAINING GAS, SAID FREE OXYGEN CONTAINING GAS BEING SUPPLIED IN AMOUNTS INSUFFICIENT TO REACT COMPLETELY WITH SAID FUEL THEREBY SUBJECTING PART OF SAID FUEL TO COMBUSTION AND GASIFYING SUBSTANTIALLY THE BALANCE OFTHE UNREACTED FUEL. 